The present invention relates to diffuser apparatus for extracting juices from juice-laden substances, especially sugarcane pith.
Many plants contain commercially valuable juices. For example, the pith component of sugarcane in its natural state is laden with sugar juice which, through suitable treatment, yields sugar. In the particular case of sugarcane, recent advances in the sugarcane processing art have enabled the recovery of sugarcane pith in an essentially natural juice-laden condition. Such advances are set forth for example, in U.S. Pat. Nos. 3,424,612 issued Jan. 28, 1969 and 3,567,510 issued Mar. 2, 1971. The ability to produce sugarcane pith in such a state has presented a unique opportunity to recover unusually high precentages of sugarcane juices with minimal processing.
In order to recover juices from sugarcane and other solid plant materials, it has been common to soak the solid material with a liquid, such as water, so as to extract soluble juices from the material into the liquid, the idea being to replace juice in the plant cells with water. Subsequently, the juice-containing liquid is treated to recover the juices. Examples of proposed diffuser apparatus may be found in U.S. Pat. No. 395,145, issued Dec. 25, 1888; U.S. Pat. No. 471,995, issued Mar. 29, 1892; U.S. Pat. No. 757,296, issued Apr. 12, 1904; U.S. Pat. No. 2,227,605, issued Jan. 7, 1941; and U.S. Pat. No. 2,567,474, issued Sept. 11, 1951. Among the various features found in previously proposed systems is the displacement of the juice-laden solid material through a liquid media. The liquid is usually in motion, with some sort of counterflow relationship between the material and liquid being established for effective juice recovery.
It has been proposed to situate a batch of the material in a compartment of a conveyor-like apparatus which revolves through reversely flowing liquid. Such operation generally involves a mininal agitation or tumbling of the product, thus limiting the efficiency of juice recovery since all portions of the material might not be subjected to the action of the liquid to the same degree.
It has also been proposed to displace a charge of the material from one liquid-filled tub to another by rotary vanes which are operably disposed in each tank. Such a system involves a high initial capital outlay and might involve a less-than-complete transfer of materials from one tank to another. Moreover, the equipment is subjected to being fouled by the liquid or materials being conveyed. In addition, material can tend to become jammed between the vanes and the tank walls, increasing the energy required to rotate the vanes.
It is, therefore, an object of the present invention to provide novel diffuser apparatus and methods for extracting juices from juice-laden solid materials.
It is another object of the invention to provide novel diffusing methods and apparatus which repeatedly tumble the materials.
It is yet another object of the invention to provide novel diffusing methods and apparatus which repeatedly tumble and squeeze the materials.
It is still a further object to provide novel diffusing methods and apparatus in which juice-laden material is repeatedly transferred between a series of tanks while being tumbled and compressed without high energy requirements and with minimal danger of equipment being fouled.